Esters of gamma-(tetrahydro-2-furyl) alkanols



United States Patent ESTERS 0F -(TETRAHYDRO-Z-FURYL) ALKANOLS Charles R. Russell, Peoria, and Lester E. Schniepp, Barringtou, Ill., and Louis S. Hafner, Indian Head, Md., and Herbert E. Smith, Peoria, 111., assignors to the United States of America as represented by the Secretary of Agriculture No Drawing. Application June 11, 1957 Serial No. 665,104

6 Claims. (Cl. 260-347.4)

(Granted under Title 35, U. S. Code (1952), see. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This application is a continuation-in-part of applica- C 3 C4119 I 4- (tetrahydro-Z-furyl) -2-butyl pelargonate having the formula a di-[4-(tetrahydro-Z-furyl)-2-butyl] adipate having the di-[4-(tetrahydro-2-furyl)-2-butyl] azelate having the formula Lem-cm-crr-o-c- (c1191 and di-[4-(tetrahydro-2-furyl)-2-butyl] sebacate having the formula ice These compounds are liquids andremain so evenat exceedingly low temperatures (low pour points), they are essentially non-volatile so thatthere is-no evaporation of the liquids from lubricated bearings even'when these are subjected to elevated temperatures, they are stable compounds and hence do not decompose when subjected to elevated temperatures as in overheated'bearings or the like, and they exhibit superior lubricating activity over'a wide temperature range as shown by their ASTM viscosity slopes and kinematic viscosity indexes. These properties make them admirably suitable'as low temperature lubricants. They also find utility as plasticizers. 7

Data illustrating these properties'is given in the following tables wherein Table I'lists the boiling and pour points, Table II lists the viscosity-temperature characteristics of the esters, and Table III lists the use of some of the esters as plasticizers for polyvinyl chloride.

TABLE I Boiling points and pour points of esters 0f4-(tetrahydr0- Z-furyD-Z-butanol Boiling Point PourPoint Ester or Melting Temp, Pressure, Point, F.

Compounderystaliized and hence would not pour at the indicated temperature.

The high stability and low volatility of the compounds is illustrated by the following test data relative to the pelargonate ester:

Stability.--On heating at 212 F. with water, 0.18 milliequivalent of acidwas liberated from 1 gram of the ester, and on heating in air .for 158 hours at 150 F., 0.005 milliequivalent of acid was liberated from 1 gram of the ester. I

V0latility.F0r this test, a '1 gram sample of the pelargonate ester was placed in a inch by /1 inch evaporating cup and placed in a forced-draft oven. It

* was found that a 1.1% loss in weight occurred on heating for 30 minutes at a temperature of F.

TABLE II Viscosity temperature characteristics of esters of 4-(tetrahydro-Z-furyl)-2-butan ol TABLE III Physical properties of polyvinyl chloride (Geon I21) films plasticized with esters of 4-( telrahya'ro-Z-furyD- 2-butan0l; 60 parts polyvinyl chloride, parts ester Low Temp. Flexi- Appearance of Film bility, F. Ester M T E S ---40 Clarity Color Odor Pelargonate 1, 060 2, 445 290 45 P P P P Clear.-. None. None. AfllpRw--...- .l 630 1, 700 300 30 P P P P d0- d0 Very light. Dioctyl phthalate (Coutrol)..- 745 2,070 320 50 P P P F do do None.

M-Moduiusat percent elongation, p. s.i. S=Percent set at break. T-Tensile strength. p. s. i. P=Pessed. E-Percent elongation at break. F==Fai1ed.

The ey-(tetrahydro-2-furyl)-alkanols used as starting materials in this invention, and methods for their preparation, are disclosed in a paper by C. R. Russell, K. Alexander, W. O. Erickson, L. S. Hafner, and L. E. Schniepp, published in Jour. Am. Chem. Soc., 74, 4543 (.1952).

Our esters maybe prepared by esterifying the required alkanol with the appropriate acylating agent. The process whichwe have employed, in most cases, has been to heat the reactants, dissolved in an inert non-aqueous solvent such as benzene, in the presence of a catalytic amount of an acidic catalyst such as p-toluenesulfonic acid. The course of the esterification may be followed by separating the water of reaction in such a manner as to enable observation of its rate and quantity. In general, the esters may be purified by distillation using conventional columns for the more volatile esters and molecular stills for those having higher boiling points.

Other physical properties of the esters and the methods by which they may be prepared are given hereafter, Table IV listing these properties.

PREPARATION OF ESTERS General pr0cedure.-To 200 ml. of benzene containing 2 g. of p-toluene sulfonic acid were added the tetrahydrofuryl alkanols and acids as indicated in the table. The reaction mixture was heated at reflux until water ceased to collect in the separating device attached between the flask and reflux condenser, after which period, the reaction mixture was cooled and 400 ml. of benzene added. The benzene solution was extracted with cold 5 percent sodium hydroxide in an amount slightly less than that calculated as necessary for the removal of excess acid and catalyst. The remaining acid was removed with 5 percent sodium bicarbonate solution, the benzene layer washed with water until neutral, and dried over anhydrous magnesium sulfate.

Butanol was added during the extraction of a number of the higher molecular weight esters to break up the emulsions which formed.

The dry benzene solutions of the esters were filtered and the solvent removed on a steam bath under reduced pressure. The crude esters were then purified by the methods indicated in the table. All of the esters which were distilled on the falling-film still were degassed for l to 2 hours at C. at .01 to .05 mm. before placing them on the still.

The yields recorded in Table IV, hereafter, are based on those fractions of the once-distilled esters having a degree of purity in excess of 95 percent, as determined by the saponification equivalent and the free acid content.

TABLE IV Esters of 'y-(tetrahydr02-furyl)-2-butzmol Properties of Purified Esters 'IHF- Method Ester of 4-(Tetrahydro-2-furyD- n Acid, Alkanol, Time, Yield, of Puri- Distillation -butanol moles moles hrs. Percent fication d 15 20 Temp, Pressure,

0. II, Hg 5 2-Ethylcaproate l O. 85 0. 6 107 38 l 97 100 l. 4437 0. 912 Pelargouate. 1 0. 75 0. 5 25 64 101 20 i. 4480 0. 912 dipatenn 2 0. 50 1. 25 7 58 r (h) 7 1. 4627 l. 025 Azelate. 2 0. 05 l. 25 48 36 5 1. 4638 1. 011 Sebacate 2 0. 50 1. 25 12 63 5 1. 4631 0. 997

Properties oi Purified Esters :o' Saponifica- Analyses Ester of 4-f'letrahydro-2- MD tion equiv.

furyD-Z-butanol Free Empirical Acid, Formula Carbon Hydrogen Percent Calcd Found Caicd. Found Calcd., Found, Calcd., Found, Percent Percent Percent Percent 78. 83 270. 4 275. 3 0.03 01031003 71.06 71. 2 11.18 11.2 83. 54 284. 4 282. 3 0. l0 (1 1E320; 71. 78 71. 3 11. 34 ll. 2 107. 2 199. 2 204 0. 68 CzzHasOe 66. 30 66. 2 9. 61 9. 7 120. 3 220. 3 217 0. 8D OuHuOa 68.14 67. 4 10. 06 10.1 125. 8 227. 3 228. 3 0. 70 CzaHnOu 68. 69 6B. 4 10. 20 10. 3

i Calculated on the basis of the once-distilled product having an analytical purity of 95+%. b Observed on final distillation, temperature of hot finger in the falling-film still; vapor temperature in all other di tlllatlons. Measured by McLeod and calibrated thermocouple gauges attached between the still head and solid 00: cooled trap.

* Measured by Fischer-Davidson gravitorneter.

' Calculated from n and d values determined at 20 C. 1 Fractionated through a jacket-heated 3-t'oot packed column. I Lowboiling impurities removed on aiembic flask still by protracted heating just under the boiling 'p'oinflat low pressures.

Distilled on falling-film still.

i Fractionated through jacket-heated 14-inch packed column.

Distilled from ulemhic tla k still.

We claim: 1. 4(tetrahydro-2-furyl)-2-butyl Z-ethylcaproate having the formula CH3 i 04H 2. 4-(tetrahydro-2-fury1)-2-butyl pel'argonate having 4. Di-[4-(tetrahydro-2-furyl)-2-buty1] azelate having the formula LCH2-CH2--CHOC (cum CH3 2 5. Di-[4-(tetrahydro-Z-furyl)-2-butyl] sebacate having the formula O ]CH2CHz-CI3HOC (CH2)x 6. A compound selected from the group consisting of 4-(tetrahydro-2-furyl)-2-butyl 2-ethyl caproate having the formula 6 4- (tetrahydro-Z-furyl) -2-butyl formula LoH2-oHl oH-0ooaHu CH3 di- [4-(tetrahydro-2-furyl) -2-hutyl] adipate having th formula CH3 2 di-[4-(tetrahydro-2-furyl)-2-butyl] azelate having the and di-[4-(tetrahydro-2-furyl)-2-butyl] sebacate having the formula pelargonate having the UCHPCHPLI'JH-O(IT (cum References Cited in the file of this patent UNITED STATES PATENTS 1,989,701 Lawson Feb. 5, 1935 2,475,592 Clark July 12, 1949 FOREIGN PATENTS 887,340 Germany Aug. 24, 1953 OTHER REFERENCES Chem. Abstracts, Vol. 42, p. 5861a (1942).

Jl f UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,864,828 December l6, 1958 Charles B, Russell et alu s in the printed specification -ied that error appear tion and that the said Letters ent requiring correc ected below.

It is hereby certif of the above numbered pat Patent should read as corr Columns 3 and 4, Table IV, third column thereof, opposite "Azelate",

for "005" read 0.50

Signed and sealed this 7th day of April 1959,

(SEAL) Attest:

KARL H, AXLINE ROBERT C. WATSON Commissioner of Patents Attesting Ofiicer 

6. COMPOUND SELECTED FROM THE GROUP CONSISTING OF 4-(TETRAHYDRO-2FURYL)-2BUTYL 2-ETHYL CAPROATE HAVING THE FORMULA 